Lack of p53 immunoreactivity in pancreatic endocrine tumors.

Abnormal expression of the p53 tumor suppressor gene has been implicated in many human epithelial tumors. However recent evidence has revealed the absence of p53 gene abnormalities or overexpression in some human endocrine cancers. This study examines the immunohistological expression of the p53 gene product using the monoclonal antibody DO-7, an antibody directed against both wild and mutant forms of p53 protein, and a streptavidin-biotin-peroxidase method, in pancreatic endocrine tumors (n = 16). None of the cases of pancreatic endocrine tumors showed evidence of p53 immunostaining. This finding is in contrast to that in pancreatic adenocarcinomas in which increased p53 immunoreactivity has been previously observed. These observations suggest that the p53 gene may not be important in the development of endocrine tumors of the pancreas.